SNAKES OF THE GENUS PITUOPHIS 27 



Diagnosis. — This form may be distinguished from lineaticollis by 

 the smaller number of ventrals (211 to 233 rather than 236 to 249 in 

 lineaticollis) and by the pattern. The presence of quadrangular spots 

 throughout the entire length of the dorsum, and the complete lack of 

 dorsal stripes, characterize deppei, while lineaticollis bears two contin- 

 uous black dorsal stripes on the anterior part of the dorsum, a double 

 series of annuli posterior to these, and a single series of annuli on the 

 posterior half of the dorsum. P. d. deppei may be separated from its 

 closest relative, jani, by the larger number of, and smaller interspaces 

 between, the dorsal spots. In the former, the spots vary in number 

 from 43 to 59 on body and tail and are separated by interspaces gener- 

 ally each fewer than four scales in length. In the latter, the spots 

 vary from 29 to 35 in number on body and tail and are separated by 

 interspaces of at least five scales in length. In common with the 

 other members of the deppei group, jani and lineaticollis, deppei may 

 be distinguished readily from all other forms of the genus by the pre- 

 sence of two rather than four prefrontals, and the entrance into the 

 orbit of two supralabials on each side, rather than one. 



Description. — Like the other members of the deppei group, this form 

 has a slender body and blunt snout. The tail length varies from 0.114 

 to 0.157 of the total length, tending to be less in females than in males. 

 The largest specimen examined was 1,790 mm. long. 



The dorsal scale formula is most often 27-29-21, but it is rather 

 variable. The maximum number for the series studied varied from 

 27 to 31 ; the number at the neck, from 25 to 29 ; the number anterior 

 to the vent, from 19 to 23. The other scale characters are as follows: 

 Ventrals 211 to 233 (average 221.8); caudals 52 to 79 (average 61.5); 

 supralabials 7 to 9 (average 8.1) with the fourth and fifth usually, or 

 third and fourth or fifth and sixth occasionally, entering the eye; 

 infralabials 10 to 14, most often 11 (average 11.9); preoculars usually 

 1, rarely 2; postoculars 2 to 4; loreal present in about 50 percent of 

 the specimens; azygos lacking between frontal and prefrontals, but in 

 two (12 percent) specimens a small azygos present on each side between 

 prefrontal and preocular; rostral as broad as or broader than long, 

 penetrating from one-third to all the distance between the internasals ; 

 frontal undivided. 



The dentition is as follows: Mandibular teeth 20 to 22, decreasing 

 slightly in size posteriorly; maxillary teeth 18, decreasing slightly in 

 size posteriorly; palatines 9 to 11, subequal and slightly smaller than 

 the mandibular and maxillary teeth; pterygoids 8 to 14, smaller than 

 the palatines and decreasing slightly in size posteriorly. 



The dorsum bears a series of large dark spots, generally quadrangu- 

 lar but occasionally saddle-shaped in the midregion. These are each 

 3 to 8 scales in length and 10 to 13 scales wide and are separated by 

 light interspaces rarely 4, and generally less than 4, scales in length. 



136423—40 3 



